Decantation fitting

ABSTRACT

A DECANTATION FITTING FOR DLUID ANALYSIS HAVING A BODY WITH AND ELONGATED RELATIVELY HORIZONTAL PASSAGEWAY PORTION WITH ONE END POSITVELY INLETTED AT A PREDETERMINED VOLUMETRIC RATE FOR A GAS-SEGMENTED SAMPLE-REAGENT STREAM AND POSITVELY OUTLETTED AT THE OTHER ENEND AT A PREDETERMINED VOLUMETRIC RATE FOR A SUPERNATANT PORTION OF THE STREAM. INTERMEDIATE THE ENDS OF THE PASSAGEWAY PORTION AND IN COMMUNCATION THEREWITH, IS AN UPWARDLY EXTENDING PASSAGEWAY PORTION POSITIVELY OUTLETTED AT A PREDETERMINED VOLUMETRIC RATE FOR THE GAS IN THE STREAM AND A SMALL PART OF THE SUPERNATANT PORTION. BELOW THE LASTMENTIONED PASSAGEWAY PORTION AND EXTENDING A DISTANCE INTO THE FIRST MENTIONED PASSAGEWAY PORTION IS A DOWNWARDLY EXTENDING DECANTATION TUBE FOR THE STREAM REMAINDER INCLUDING PRECIPITATE OR SETTLED-OUT MATERIAL THEREIN.

Dec. 14, 1971 ADLER' JR" ETAL 3,62?,45

DECANTATION FITTING Filed May 25, 1970 u. INVENTORS 38 STANFORD I AOHRJR JOHN CA PEOPHC J) ATTORNEY United States Patent Ofice 3,627,495 DECANTATION FITTING Stanford L. Adler, Jr., Monsey, and John C. A. Peoples,

Nanuet, N.Y., assignors to Technicon Instruments Corporation, Tarrytown, N.Y.

Filed May 25, 1970, Ser. No. 40,063 Int. Cl. G01n 33/16 US. Cl. 23-253 R 5 Claims ABSTRACT OF THE DISCLOSURE A decantation fitting for fluid analysis having a body with an elongated relatively horizontal passageway portion with one end positively inletted at a predetermined volumetric rate for a gas-segmented sample-reagent stream and positively outletted at the other end at a predetermined volumetric rate for a supernatant portion of the stream. Intermediate the ends of the passageway portion and in communication therewith, is an upwardly extending passageway portion positively outletted at a predetermined volumetric rate for the gas in the stream and a small part of the supernatant portion. Below the lastmentioned passageway portion and extending a distance into the first-mentioned passageway portion is a downwardly extending decantation tube for the stream remainder including precipitate or settled-out material therein.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to a decantation fitting for use in fluid analysis systems in which gas-segmented samplereagent streams flow; and in which streams particulate matter may be separated by gravity, or matter may be separated as in precipitation.

(2) Prior art Apparatus for the continuous analysis of fluids are well known. Such an apparatus is disclosed in US. Pat. 2,797,149, issued June 25, 1957. US. Pat. 2,879,141, issued Mar. 24, 1959, discloses an analysis apparatus of an automated type in which samples are fed in a flowing stream by means of an offtake device which aspirates liquid from each of a plurality of sample containers which are sequentially presented thereto by a sampler assembly. Such apparatus is commonly employed for the analysis of body fluids. Similar apparatus is employed for other analytical purposes such as monitoring industrial operations, for example.

In many such types of analyses, 21 settling or precipitation occurs in the flowing sample stream. For example, red blood cells may be agglutinated or aggregated as in blood typing determinations or in the screening of blood for atypical antibodies. It is common to segment such precipate-containing streams with air or an inert gas employed for the purpose of maintaining sample integrity and isolation, and also for cleaning the conduits in which such streams flow.

Further, it is traditional to separate certain components of such streams by decantation, as illustrated and described in US. Pat. 3,334,018, issued Aug. 1, 1967. Such a decantation fitting is shown in FIG. 2 of the drawing of the last-mentioned patent. This fitting allows agglutinated red cells in each liquid segment, separated from its neighbours by gas segments or bubbles, flowing in a tube through the action of a pump, to fall by gravity into another tube in communication with the first-mentioned tube, which is subjected to negative pressure. The supernatant liquid, together with the gas bubbles, passes off from the first tube at the outlet end thereof together with 3,627,495 Patented Dec. 14, 1971 any residual agglutinated cells. The separation of the aforementioned components of the stream is not as efiicient as it might be and is lacking in reproducibility to the extent which it is desired to achieve.

SUMMARY OF THE INVENTION It is an object of the invention to provide a decantation fitting for separating components of a stream such as described and which employs a debubbling feature to enhance decantation of the supernatant liquid from the agglutinated material when employed, by way of example, in a system for an analysis such as that described in US. Pat. 3,334,018 supra, but which is not limited thereto or to the separation of an agglutinate. In the debubbling action, the bubbles, in accordance with the invention, actually push the precipitate or agglutinated cells into a decantation tube which has a beveled end protruding into the stream and with which the bubbles sequentially co-act as they pass into a gas-removal stream over the last-mentioned decantation tube, while the supernatant portion of the stream passes beyond the aforementioned decantation tube. The gas and supernatant streams of the fitting are positively outletted so that the aforementioned decantation tube is outletted by a volumetric rate differential.

Decantation by this fitting has relatively high reproduci bility, and more effective decantation is provided. The fitting is of relatively simple and economical construction.

The fitting includes a body portion with an elongated relatively horizontal passageway having one end positively in'letted at a predetermined volumetric rate for a gas-segmented stream of treated liquid and positively outletted at the other end at a predetermined volumetric rate for a supernatant portion of the stream. An upwardly extending passageway is provided intermediate the ends' of the first-mentioned passageway and in communication therewith, which is positively outletted at a predetermined volumetric rate for the gas in the stream and a small portion of the supernatant stream. Co-acting with the lastmentioned passageway and located there'below, extending a distance into the first-mentioned passageway, a downwardly extending decantation tube is provided for the stream remainder including precipitate therein.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is diagrammatic view of fluid analysis apparatus incorporating a differential decantation fitting embodying the invention, and

FIG. 2 is a fragmentary, greatly enlarged view in elevation, partially in longitudinal section, of the decantation fitting.

DESCRIPTION OF THE PREFERRED EMBODIMENT .diameter of the bore 11 is .080 inch. Substantially midway between the ends of the latter, the body 10 is provided with a vertical bore 12 in communication with the first-mentioned bore and having an internal diameter of .154 inch.

The portion of the body forming the bore 12 is provided with an externally tapered outlet nipple 13 for connection to a suction line of the fluid system. A similar nipple 14 is provided on the body at the inlet end of the bore 11, and at the outlet end of the last-mentioned bore, a similar nipple 15 is provided.

Below the bore 12 of body 10, there is provided a vertically arranged tube 16 extending into the bore 11 in the manner shown in FIG. 2. The tube 16 is preferably formed of non-corrosive metal such as stainless steel and may take the form of a hypodermic needle having the beveled end thereof projecting into the bore 11. The tube 16 has an internal diameter of .020 inch, and the tube 16 is secured in the body 15} as by a press-fit in a suitably drilled bore in the body. It will be apparent from the foregoing that the body with the bore 11 and the bore 12 may be formed of tubular glass parts, suitably fused together, or otherwise secured, and suitably receiving and secured to the metal tube 16.

The construction and arrangement of the tube 16 in the body 10 is important. The end 17 of the tube should be beveled at an angle of substantially 45 as shown, with the bevel arranged so as to incline downwardly toward the inlet end 14 of the fluid passage 11. The lowest extremity of the bevel should be in line with the bottom of the bore 11. The spacing between this extremity of the bevel and the point of the bore 12 nearest the inlet 14 must be equal to or greater than the diameter of the bore 11. It is preferably in the range of .080 to .095 inch.

This spacing requirement results in the nonconcentricity of the tube 16 with reference to the bore 12 which is apparent in FIG. 2. Further, the reason for this spacing requirement will be apparent from an examination of FIG. 2 wherein the gas present in the bore 11 is in the form of bubbles G, separated from one another, of a size to extend across the diameter of the bore 11. It is important that the gas of these bubbles separate and. isolate for sample integrity portions of the stream therebetween while, at the same time, it is important to inhibit this gas finding its way down into the tube 16, a situation which might occur in the use of the decantation fitting of aforementioned US. Pat. 3,334,0l8. Such entrainment of gas in the tube 16 would result in excessive gas in the fluid system downstream of the decantation fitting which would result in noise in the signal output as will be apparent hereinafter with reference to the described use of the decantation fitting in a fluid analysis system.

To effectively tend to insure that all the gas previously introduced into the stream flowing into the inlet 14 is removed in the decantation fitting, the bore 12 of the fitting and the volumetric flow through the outlet of the nipple 13, associated therewith, is such that slightly more fluid is removed by the fitting through the bore 12 than the volume of gas previously introduced into the system. This results in the removal in a bore 12 of a small amount of the supernatant liquid with the previously introduced gas. The volumetric flow rate at the outlet of the fitting is suflicient to remove substantially all of the supernatant liquid. As the gas bubbles pass from the bore 11 to the bore 12, they sweep up the beveled surface of the tube 16, previously described, forming a ramp, following the line of least resistance, entering the bore 12 from which gas is removed in the aforementioned manner. In moving in this manner, the gas bubbles sweep the settledout or agglutinated material into the last-mentioned end of the tube 16, for removal of this material by the difference between the input in the inlet 13 and the total volumetric outlet rates of the outlets 13 and 15. For example, the input at the inlet 14 may be 3.52 ml. per minute; the output at outlet 13, 1.2 ml. per minute; the output at outlet 15, .8 ml. per minute; and the output through tube 16, 1.52 ml. per minute.

It should be noted that the portion of the end 17 of the tube 16 which provides an upwardly diminishing transversely arced surface, owing to the bevel of the tube end, which is arranged in opposing relation to the fitting inlet, very effectively acts as a trap for settled-out ma terial. This material which, as it is carried along in the stream in bore 11, is trapped by the last-mentioned surface passes into the tube 16 in a downward direction. It passes into the tube 16 in a far more effective manner than would be the case without the aforementioned tube pro ection into the bore 11. The volumetric rate of flow in the tube 16 may be predetermined in accordance with the volumetric input of sample and reagent upstream and the anticipated volume of material which may be settled 111 the lower portion of the stream.

It is noted that apart from the aforementioned concept of the positively inletted and outletted bore 11 and the positively outletted bore 12, wherein the volumetric rate of flow in the outlet 16 makes up the difference, there 18 provided a simple and effective stream divider ncluding a gas-segment-deflecting element which in the illustrated form is embodied in the beveled end 17 of the tube 16 which projects into the bore 11.

The use of the differential decantation fitting of FIG. 2 will now be explained with reference to the fluid analysis system shown in FIG. 1. According to the fluid analysis system of FIG. 1, briefly described, the liquid sample, in the form of a stream, is treated with a processing liquid during the flow of the sample, and the processing liquid s of a type which forms a substance in the stream which is separable from the stream because of the greater spec fic gravity of the substance in relation to that of the liquid of the stream. The presence and amount of such a formed substance is an indication of the effect of the processing liquid on the liquid sample and, during the flow of the treated stream, at least a major portion of the separable substance is removed therefrom, and the stream is thereafter analyzed to provide a measurement of the effect of the processing liquid on the sample.

The disclosed fluid analysis system of FIG. 1 is especially useful for, although not limited to, the determina tion of blood types. As is well understood, type A blood is responsive to type A anti-serum, type B blood is responsive to type B anti-serum, and type 0 blood is not responsive to either of these anti-sera, so that when type 0 blood is treated with either type of anti-sera, no agglutination of the red cells occurs. When either type A or type B blood is treated with its correspondingly identifying anti-serum, the red cells of the blood agglutinate. This agglutination reaction of the red blood cells is utilized in the disclosed fluid analysis system for determining blood types.

More particularly, a series of unique sanguineous samples, such as blood samples, more particularly red cells of unknown types, in the form of a stream is treated with a particular anti-serum, for example type A. The samples which are type A react to the type A anti-serum and agglutinated red cells are formed therein while the type B and 0 blood samples do not react and, therefore, no agglutinated red cells are formed. The resulting stream of anti-serum treated blood cells is passed through a series of separating devices, more particularly, decantation devices, which remove the relatively denser, agglutinated red cells from the samples. Thereafter, the blood samples of the resulting stream are hemolyzed and the stream is colorimetrically analyzed with respect to its hemoglobin content. Those blood samples which are type A will indicate a relatively low hemoglobin content due to the removal of the agglutinated red cells, while the blood samples which are not type A indicate a much higher hemoglobin content, since no agglutinates of red cells were formed. In this manner determinations of blood types can be made accurately and in a relatively simple and expeditious manner.

The apparatus comprises a proportioning pump 20 of the resiliently compressible tube type, a horizontal helical mixing coil 22 formed of glass tubing or other suitable material, and identical mixing coil 24, a vertical helical time-delay and settling-out coil 26 of tubing formed of glass or other material which may be immersed in a temperature controlling bath, not shown, the decentation fitting of FIG. 2 including the aforementioned body 10, an-

other horizontal mixing coil 28, another vertical timedelay and settling-out coil 30, a decantation fitting 32 identical to the decantation fitting 20 of FIG. 2 of Pat. 3,334,018, supra, a time-delay and settling'out coil 34 shorter than the coils 26 and 30, a decantation device 36 identical to the decantation device 32, another mixing coil 38 similar to those previously described, a conventional colorimeter 40 having a flow cell (not shown) therein, and a recorder 42 operable under the control of the colorimeter.

The foregoing components of the apparatus are connected in fluid-flow communication with each other for the continuous treatment and analysis of one or more blood samples, more particularly red blood cells, which are supplied in the form of a stream to a pump tube 44 by a suitable liquid sample supply device such as previously described. It will be understood that the blood samples are longitudinally spaced from each other in the stream, and that each is separated from another by an intervening segment of air, provided by the operation of the sample supply device.

Simultaneously with the supply of the samples to tube 44, air is supplied to pump tube 46 and the anti-serum is supplied to pump tube 48. The fluids join each other at fitting 50 and a segmented stream is formed consisting of longitudinally spaced liquid segments, each containing a portion of the sample and anti-serum, and the liquid segments are separated from each other by an intervening air segment which, as previously described, helps maintain the internal walls of the tubular passages of the apparatus clean to prevent contamination of a sample due to deposits of material from a preceding sample. The segmented stream is transmitted from fitting 50 to the mixing coil 22, which has a relatively short flow path, for mixing the constituents of each liquid segment together.

Pump tube 52 supplies diluent to the stream downstream of the coil 22 and upstream of the mixing coil 24 to which the stream then passes. Each liquid segment is mixed in the coil 24. The stream then passes to the settling-out and time-delay coil 26. Coil 26 has a series of substantially horizontal convolutions that provide a relatively long fiow path for the streamto provide time for the reaction of the blood samples of the type corresponding to the anti-serum. As indicated previously, the reaction results in agglutination of the red cells in the blood sample and clumps of the red cells are thereby formed in an amount depending upon the effect of the anti-serum on the blood sample. As the sample travels through the convolutions of the last-mentioned coil, the relatively heavy agglutinated red cells settle at the bottom of the stream as described in US. Pat. No. 3,334,018, supra.

The reacted stream, containing the settled-out or agglutinated red cells, is transmitted from the bottom of coil 26 to the body of the differential decantation fitting best shown in FIG. 2 through the inlet 14. The stream is debubbled as aforesaid, with the gas being removed through the outlet 13 by a pump tube 54. The supernatant liquid leaves the outlet of the fitting in the aforesaid manner, through pump tube 56. The agglutinated red cells leave the differential decantation fitting in the aforesaid manner, through the tube 16 connected to the inlet of the coil 28 as shown in FIG. 1.

However, air is introduced in the line through pump tube 58 for wash purposes, intermediate the outlet of the tube 16 and the mixing coil 28. Saline solution for the dispersion of false agglutinate is introduced in the line through pump tube 60, intermediate the last-mentioned air inlet and the coil 28. Mixture occurs in the coil 28 in each of the sample segments of the resulting stream separated by air bubbles last introduced, and any unagglutinated red cells which have settled out are again suspended in the liquid.

The stream is transmitted from the mixing coil 28 to the aforementioned coil which permits additional agglutinated red cells to settle out to facilitate the removal of the agglutinated red cells at the aforementioned decantation fitting 32. The agglutinated material passes through outlet 62 of the fitting 32 by means of pump tube 64. The efiiuent flows from the decantation fitting 32 to the shorter time-delay and settling-out coil 34 in which any carry-over of settling-out or agglutinating material tends to fall to the bottom of the stream. The stream passes from the last-mentioned coil into decantation fitting 36, previously described, having its decantation outlet 66 connected to pump tube 68 for the removal of additional settled-out or agglutinated red cells.

Pump tube 70 connects to the efiiuent stream from the decantation fitting 36 to supply a hemolyzing agent to the stream which still contains air or gas bubbles and is segmented thereby. The stream passes next through mixing coil 38 in which each of the treated liquid segments is mixed, and the stream passes next to the colorimeter 40 wherein the hemoglobin content of the samples is colorimetrically determined in a conventional manner after the removal from the stream of the gas bubbles to waste through tube 72 in the usual fashion. If desired, the gassegmented stream may pass through the flow cell, not shown, of the colorimeter. The pull-through of the flow cell is connected to pump tube 74.

The recorder 42 is conventionally connected to and operated by the colorimeter 40 to record the colorimetric analysis of each sample with reference to its hemoglobin content which indicates thereby whether or not an agglutination-type reaction has taken place. As previously explained, the blood samples which are type A react to the type A anti-serum and agglutinated red cells are formed therein while type B and 0 blood samples do not react, and therefore, no agglutinated red cells are formed. The samples which are type B react with type B anti-serum, and neither type A anti-serum nor type B antiserum react with type 0 blood samples.

While only one embodiment of the invention has been illustrated and described, it will be understood that the invention may take other forms and is susceptible to various modifications and changes within the skill of those versed in the art, without departing from the principles of the invention.

What is claimed is:

1. Apparatus for fluid analysis comprising first means defining an elongated, relatively horizontal first passageway portion having one end positively inletted at a predetermined volumetric rate for a gas-segmented, samplereagent liquid stream and positively outletted at the other end thereof at a predetermined volumetric rate for a supernatant portion of the stream, second means intermediate the ends of said first passageway portion defining an upwardly extending second passageway portion from said first passageway portion, positively outletted at a predetermined volumetric rate for the gas segments in the stream and a small part of the supernatant portion, and third means below and substantially aligned with said second passageway portion including a trap for settled-out material in the lower portion of the stream, said trap including a third passageway portion for the egress of said material from said first passageway portion at a volumetric rate which represents the dilference between said inletted volume and the total of said positively outletted volumes and, also, extending into said first passageway in an upwardly diminishing, transversely arced surface in opposing relation to said inlet for contact with said gas segments, along which said gas segments move toward said second passageway portion, said second and third passageway portions having respective axes perpendicular to the axis of said first passageway portion.

2. Apparatus as defined in claim 1, wherein said third means is constituted by a hypodermic needle having the beveled end portion thereof forming said trap and arranged in opposing relation to said inlet, and occluding only the lower part of said first passageway portion, said needle having its axis perpendicular to the axis of said first passageway portion.

3. Apparatus as defined in claim 1, wherein said third means is constituted by a tube having a sloping end portion projecting into said first passageway portion and arranged in opposing relation to said inlet thereof.

4. Apparatus as defining in claim 1, wherein said third means is constituted by a tube having a sloping end portion projecting into said first passageway portion and arranged in opposing relation to said inlet thereof, said slope being formed on an angle of approximately 45 to the axis of the tube.

5. Apparatus as defined in claim 1, wherein said third means is constituted by a tube having a sloping end portion projecting into said first passageway portion and arranged in opposing relation to said inlet thereof, said slope being formed on an angle of approximately 45 to the axis of the tube, said second passageway portion being larger in diameter than the first, and said sloping portion of the tube terminating at the bottom of said first passage- References Cited UNITED STATES PATENTS 2,967,764 1/1961 Skeggs 23253 3,047,367 7/1962 Kessler 23230 3,334,018 8/1967 Srnythe 23-230 BIO MORRIS O. WOLK, Primary Examiner R. E. SERWIN, Assistant Examiner US. Cl. X.R.

2323O R, 230 B, 259; 21048; 424l1 

